1. Field of the Invention
The present invention relates to a switch to be mainly used to operate various types of electronic equipment.
2. Background Art
In the recent promotion of downsizing and enhancing the functionality of various types of electronic equipment, such as a portable telephone and a personal computer, a small, thin switch capable of ensuring reliable operation is also required for operating such equipment.
A description is provided of such a conventional switch with reference to FIGS. 6 through 8.
FIG. 6 is a sectional view of a conventional switch. FIG. 7 is a perspective view of the conventional switch. With reference to FIG. 6 and FIG. 7, case 101 made of an insulating resin has an opening on the top face thereof, and substantially a box shape. Fixed contact 102 is formed of a conductive sheet metal. A plurality of fixed contacts 102 are implanted on the inner bottom face of case 101 by insert molding or the like.
Operating body 103 made of an insulating resin is housed in case 101 so as to be movable horizontally. Operating part 103A is projected from a side face of case 101.
In movable contact 104 made of a resilient sheet metal, the central part thereof is fixed onto the bottom face of operating body 103. In substantially a deflected state, both ends of movable contact 104 are in resilient contact with the central and right ones of fixed contacts 102. Thus, switch contacts are formed.
Cover 105 made of a sheet metal covers the opening on the top face of case 101. Terminals 106 extending from fixed contacts 102 and projecting outwardly from the ends of case 101 are bent upwardly from the base portions thereof. Thus, switch 107 is formed.
FIG. 8 is a sectional view of the conventional switch mounted on a wiring board. With reference to FIG. 8, a plurality of wiring patterns (not shown) are formed on the top and bottom faces of wiring board 108. On the top face of the wiring board, a plurality of lands 109 are provided at intervals each smaller than the dimension of switch 107. On lands 109, the bottom faces of the ends of case 101 and terminals 106 are placed.
Cream solder or the like is applied to the top face of each land 109 and heated to form solder layer 110. By solder layers 110, the plurality of upwardly-bent terminals 106 are electrically connected to lands 109, and mechanically bonded thereto. Thus, the conventional switch is formed.
The thus formed conventional switch is placed behind a control panel (not shown) of electronic equipment so that operating part 103A projects from the control panel. Terminals 106 are electrically connected to the electronic circuits (not shown) of the equipment via the wiring patterns on wiring board 108, or the connectors, leads, or the like (not shown) connected to the wiring patterns.
When operating part 103A is slid in the left direction, movable contact 104 fixed onto the bottom face of operating body 103 moves in the left direction and both ends of the movable contact make resilient contact with the left and central ones of fixed contacts 102. Thus, the switch contacts are changed over. Then, this electrical signal is supplied from terminals 106 to the electronic circuits of the equipment via the wiring patterns or the like, so that various functions of the equipment are switched.
Even when a slightly large force is applied to operating part 103A during such operation, solder layers 110 formed between upwardly-bent terminals 106 and lands 109 prevent terminals 106 from peeling off from lands 109 and prevent switch 107 from coming or floating off from wiring board 108. In other words, in the structure of the conventional switch, the strength of bonding terminals 106 to lands 109, so-called terminal strength, is enhanced by upwardly bending terminals 106 that project outwardly from the ends of case 101 and forming solder layers 110 between terminals 106 and lands 109.
Japanese Patent Unexamined Publication No. 2003-297183 is an example of the known document information on the conventional techniques related to this invention.
However, in the conventional switch, the sizes of solder layer 110 formed between terminal 106 and land 109 are likely to vary with the amounts of applied solder. For this reason, it is difficult to obtain sufficient terminal strength.